NOTE : Updated February 12th 2019 - for quick infos please scroll down to "III/Current state of the build" or last page; if you have time look through my development or my thread for more detailed updates.

Hi guys, welcome to my build thread

I/ What is this thread about

(2019 February version)

A/Introduction

Thanks to ES awesome community who generously shares key knowledge. Special thanks to JohninCR for his teachings in motor, Vedder for his awesome work in micro ESC, torqueboards for his help on understanding power distribution/use with multiple motors layout, and everyone who kindly helped me on the way !

This thread is getting older : in 2015 I've started working on building Ariane Treks (and for this build thread, AT-One). It's my take on a realistic and practical application of motorized skates imagined in the manga Air Gear (yep).

It also consists in highly powered electric inline skates. Take everything you love in skates. Then boost it all.

When you want something and you can't buy it, you build it.

B/Without control, power is nothing

You should not control inline skates with a RC transmitter or a command like you do with a longboard. It is not intuitive, your reactions are delayed, you can't predict what you are doing because your legs suffer from an artificial rythm you try to control with your finger... instead of putting up the rythm like you normally do when you ride classic skates.

Thus I aim to develop a hands free control for my skates. Simply let your body do the job and focus on riding. The skates must obey this rule. That's my actual goal, to make the rider forget about the electric stuff and just enjoy the adrenaline.

C/So, let's talk numbers, what power do we talk about?

My current rig packs 2x custom E-Max GT4020 50mm. More motors options and layouts in the trunk, but you have to start somewhere.

The controllers used are now based on Vedder's VESC hw6.4 + double air-cooled heatsinks. Reliable and flexible controllers & a lot of power in a tiny package (under 50x50 or 60x60 approx).

The GT4020 are 1600W factory rated at 8S / 33v. Nice power to weight ratio. BTW my mule units are under mods. Wider gauges, extra cooling. Extra magnets. Should define a high continuous power rating and nice torque.

Once it runs I'll up the voltage for more punch and top speed.

D/Going fast is cool. Being able to commute for the day and ride back home is cooler.

Let's talk batteries ! This is specific to AT-One.

My first battery pack is made of LG HB2 18650 cells (30A capable, cool discharge temps, but low 1.5Ah/cell capacity). That's enough for a not too heavy pack with power on demand.

Note : bigger batteries are possible. For example I'd like to try the new Turnigy Graphene batteries, super durable, lot of power and sag is non existent + long cycles.

Only limit in choices is weight cause I don't want heavy skates.

So far best layouts with 18650 cells would be 8S to 12s2P. Hot swap packs so no need to bring more Wh.

Still got side stuff on the table to do, i.e. a break chopper to have endless regen even with full battery.

E/Custom it like you stole it. Hub motors and one frame to size them all.

Have you ever wanted to not be limited by any choice of boot? Be it 165, 180, UFS or Trinity ? If so, why compromise ?

I'm bringing "Universal" to a new standard. Just choose your favorite style boot and brand ! My own skates are so far :
- Roces M12 (needs an update, these are still in very nice shape)
- Doop FR3 (it's in shambles and waits to be put together again)
- Flying Eagle F110 (my new weapons, these skates nail it 100%)

The frame is designed to accomodate the powertrain, not the other way around.

It comes loaded with a quick swap system : I'm confident in saying that switching between boots & wheel sizes has never been so easy and fast.

Up there I said I was developing hub motorisation. I worked my way through to get motors with low profile between 20-30mm width to fit right inside the skate wheel. That's where the custom GT4020 and siblings models come in play.

Previously I started this with Roces Majestic 12 from my good old days. Then I upgraded to Doop Freestyle 3 because I needed more versatile and lighter ride. Yet a bare boot is 1kg100. With a Supra sneakers inside it rockets up to 1kg600. That's heavy right.

So with my heavy 1600gr boots the 8S version accounts for 3Kg per foot without lightening mods. Seems too fat right ?

Here is the feat : weight of March 2017 did hit 2.55kg per skate for 8S model without lightening mods with a light freeskate boot.

It has become, in fact, lighter than most EVs I know.

So in the end the difference in sensation between a classic skate and these will mainly be about the motor power, not the extra weight.

That's all for now, thank you for reading till there

II/ Current state of build

-Custom 85Kv low profile motors mounts are working
-Hub rims are SLEEK as EFF
-Hub motors v4 under work
-Frames redone AGAIN, had to solve problems with previous parts + lower CG + make it stronger
-Custom solderless battery modules ready to roll
-Controllers based off VESC hw 6.4, these are monsters in the size of a CB card

Last edited by Vanarian on Feb 28 2019 5:19am, edited 70 times in total.

Wow, this is very cool! Thank you for the video, it is really inspiring! Using open skates is also a good idea, I was thinking of getting a pair of XSjado or Doop skates to make a more "civilised" version.. You prove that it is a good idea

Finally a video showing some real use of electric inlines, I swear that after a night of work this was a breeze of fresh air for me. Thank you very much!

EDIT : By the way I see that this is your first post here so... WELCOME ABOARD

I finally registered here in ES, but I have been reading this forum for a while. Truth is since I started building the ThundrBlade I've looked everywhere in the internet for information. I even checked patents for info.

About the LandRoller suggestion, I had Land Rollers before. they feel different from normal inline skates, they are good, practical and a lot of fun, but not the same maneuverability. I dont think you could make hub motors work diagonally like that. maybe it can work. I dont know.
You could use the motors elsewhere and transmit the power trough gears, but that would add a lot of noise.

well, I expect to build a new prototype with double the power in 1 month or so, I will make new clips as I have progress.

ps: I love the powerslide open boot design, mine are not doops, but they are from the Nordic Skating but they are very similar to doops.
ps2: I gave up on using UFS and went for a normal 165mm mount, I think for a product its a better choice.

The bigger wheels are much more suited for speed and road imperfections.

Fewer faceplants maybe.

Maybe easier to add a motor also.

Only downer is that a lot of the popular sizes are sold out. Can find some on ebay. Rumor is a new improved 2015 model is coming out.

Ryuudan wrote:yeah. no problem. hope your build hasnt stalled.

I finally registered here in ES, but I have been reading this forum for a while. Truth is since I started building the ThundrBlade I've looked everywhere in the internet for information. I even checked patents for info.

About the LandRoller suggestion, I had Land Rollers before. they feel different from normal inline skates, they are good, practical and a lot of fun, but not the same maneuverability. I dont think you could make hub motors work diagonally like that. maybe it can work. I dont know.
You could use the motors elsewhere and transmit the power trough gears, but that would add a lot of noise.

well, I expect to build a new prototype with double the power in 1 month or so, I will make new clips as I have progress.

ps: I love the powerslide open boot design, mine are not doops, but they are from the Nordic Skating but they are very similar to doops.
ps2: I gave up on using UFS and went for a normal 165mm mount, I think for a product its a better choice.

Don't worry my build hasn't stalled, I'm taking time because I can't fund everything at once (and it was a good thing because if I did this, I wouldn't have been able to get VESCs or I'd have wasted money on unused controllers )

Thank you for the feedback about open boots and Landrollers, I have never riden these before. Actually haven't met anybody with Landrollers too, might consider it later. It is possible to motor them but I don't know how it will perform since there will be weight distribution around the boot and not only at the wheels. It could kill the benefits from the LandRollers conception.

I'll definitely give a shot to Doop skates, but I try my best to keep UFS for easy maintenance.

Yo~ got a bit of free time today and seeing that I still wait for most of my parts has bored me so I figured I could take a quick shot of my boots and wheels sets, if you wonder what kind of sizes it represents in real life. Please forgive my bad accent

Vanarian, I'm here Ryuudan, I can see that your working on a friction drive eh haha~.....Van, could you tell me that the 5020 would run on how many specific volts and amps?? And, how did you run it?? I'm still new to these stuffs....

chinyp wrote:Vanarian, I'm here Ryuudan, I can see that your working on a friction drive eh haha~.....Van, could you tell me that the 5020 would run on how many specific volts and amps?? And, how did you run it?? I'm still new to these stuffs....

For sure! About voltage and amperage, what you must keep in mind is that you should not go above power ratings made by the factory because you will produce too much heat, lose power and strongly risk killing motors. It can be different story with huge motors but with our tiny sized outrunners it is important.

Voltage produces eddy currents (iron losses) and Amperage produces square currents (copper losses), the more you lose the more you waste power into heat. Copper losses rise easily higher than iron losses. In short the higher your voltage the lower your amperage thus the better you will be with your motors.

The 85KV motors I ordered with the group buy are rated for 6S so minimum recommended is 6S (because under this level you will need too many Amps thus produce way too much heat). Personnally I intend to run it between 10S and 14S depending on both power level and battery chemistry (see in cells form there are many options available like Li2Hpo4, LiFepo4, Li-Ion, Li-MP...). I don't intend to go above 1600W but I need to test them once arrived to see how much power these can release. Best for me is to try and get the less amps possible because it will drastically lower heat inside the motors.

My bottleneck is the continuous ratings given for amperage and voltage discharge of the VESC. So I sized BMS accordingly and batteries too.

BTW the VESC is an electronic controller made by Vedder, it actually manages all the motor's timings and needs and it is pretty awesome and compact, perfect for the job. You should check the relevant thread it is titled "10S custom ESC : testers needed!"
And the BMS is a battery management system, it does all the foolproof job for you when you charge and discharge your batteries. With this it is kinda as easy as plugging a smartphone when you want to charge your e-ride.

Thank you for the 3d printer I've waited a long time to get my hands over one, I can't wait to make it work! I need to order filaments first (and the seller must send me accessories).

So, about the Low KV issue.. not sure if you plan on running a pulley setup with it as well and/or by itself..

I do notice though that the lowest KV isn't always the best. I was testing some lower KV motors with high gearing for more torque and notice it actually struggles to go up a hill especially if you happen to stop in the middle of the hill.

The reason for this is because of the gearing + low KV, it not able to turn the wheels fast enough to get any traction or momentum. So the a bit higher KV would of fixed the issue and I can fly up the hill with less stress on the motors.

So in reality, we should be running mid KV range and change the gearing to adjust IMO.

Not sure if your running a pulley setup but just FYI.

I'm sure, your more technically inclined then myself but just what I've noticed.

That's a strange issue, not sure to understand ; when you say momentum / traction do you mean that it was too slow to keep up with the pace taken before starting the climb (or that it couldn't allow a fast enough pace) and that in case of stop in the middle of the hill it could not slip the wheels a bit in order to take some speed and get started again?

I want to run the 85KV by itself (because it is compact enough to fit like a hub) but I thought also of planning low KV in bigger outrunners which should be belt/pulley-driven, so for mid-drive you do recommend a mid KV not too low? I was thinking of something around 130Kv, is it already too low or with proper gearing do you think that it is ok?

I think if you run the 85KV by itself w/ no gearing. It should be fine but if you run it with gearing and a high torque gearing 1:3 or so then it will have issues going uphill. You can probably use 1:2 and or closer to 1:1 but I still think higher KV is better because you run into the issue w/ the added drag and spinning resistance of a lower KV motor.

I think it's similar to Ben's calculation of 8000RPM. Lower KV motors actually cause more drag due to being lower KV but offer more torque. They spin less freely (so it seems).

So I think just going uphill (15%+ incline) with the added load of 180-200 lbs person too low of KV doesn't spin the motors fast enough to climb the hill faster and/or go up the hill normally. It's just too slow especially with the load and lower KV to gain any momentum. So you can pause in the middle of the hill and/or slow down but to re-accelerate and move forward it bogs down.

I'm sure, on flat ground you'll have more torque but for hills I don't think it works out but works against you.

Ex. 240lbs single motor 10S. 192KV motor struggles to bring him up a 15% incline versus a 260KV motor flies him up the hill with the exact same setup. Sure, gearing ratios differ but it makes sense. *Might be a 149KV/162KV motor or lower than 192KV. IMO 192KV should still be fairly fine. Can't remember exactly.

I honestly think 230KV is the sweet spot IMO. You can go up and down from 6S to 12S and 1:2 to 1:3 variations with ease. The setup should run perfectly fine going uphill/downhill you can adjust from gearing ratios.

I want to run the 85KV by itself (because it is compact enough to fit like a hub) but I thought also of planning low KV in bigger outrunners which should be belt/pulley-driven, so for mid-drive you do recommend a mid KV not too low? I was thinking of something around 130Kv, is it already too low or with proper gearing do you think that it is ok?

Just go hub all the way my friend, especially now that you have connections with the motor manufacturers. It's the way of the future. Don't worry about the low kv, just slap higher voltage on them and they will tackle anything. The formula of low kv motor + higher voltage has been proven on E-bikes, and gives you the whole range of performance from low speed to high speed. Higher voltage also give you more range, just look at Boosted's range of 6 miles on 2500mah batteries and dual motors. They get that from the 40 volts.

The thing with high kv motors is that they like to spin fast or else they will heat up when you try to run them at low speed with load. So then people gear them down with like a 4:1 reduction so that they don't go flying off to the sunset. Well, that's good for acceleration, but what about coasting and braking? With that tall gearing, when you let go of the throttle the bigger pulley wheel pulley will spin 1 revolution while the motor's pulley will spin 4. Those magnets will really bite and slow you down, that's why you have that forward-lurch when you let go of the acceleration. And when you're going downhill and brake all of a sudden, the big wheel pulley carrying your momentum will still try to spin the motor's pulley even though it wants to stop. If the motor pulley doesn't give in, your belts may and they will skip and hop over the teeth. Hub motors don't have these things.

Didn't think of it sooner but that's Right if the slim 50mm 85Kv perform well since I got already in touch with the manufacturer I can always negotiate whole new motors like 60-70mm with slim profile between 20-30mm of width for bigger power !

My motor!!!! I'm super sad that I couldn't get my hands on those motors T_T..... I plan to get my hands on these motors first before I could do anything else~ Van, if you really did wreck that motor....could you mail it to me?? Haha
I wan to use those dimensions to make my geared hub....
Btw, where and which manufacturer you sourced it from? How much was the surcharge you mentioned?? I wanna just order it and pay for the surcharge....desperate and impatience here....

Pediglide wrote:
Just go hub all the way my friend, especially now that you have connections with the motor manufacturers. It's the way of the future. Don't worry about the low kv, just slap higher voltage on them and they will tackle anything. The formula of low kv motor + higher voltage has been proven on E-bikes, and gives you the whole range of performance from low speed to high speed. Higher voltage also give you more range, just look at Boosted's range of 6 miles on 2500mah batteries and dual motors. They get that from the 40 volts.

Higher voltage does not give you more range. It's slightly more efficient then a low voltage setup but that's offset by the cost of high voltage esc and high voltage chargers. Boosted's 6 miles on 2500mah at 40v equals 16.7 w/h per mile which is about the same as other e-boarder with their DIY builds. The e-bike guys who use rc outrunners get similar watts per mile as well.

Higher voltage does not give you more range. It's slightly more efficient then a low voltage setup but that's offset by the cost of high voltage esc and high voltage chargers. Boosted's 6 miles on 2500mah at 40v equals 16.7 w/h per mile which is about the same as other e-boarder with their DIY builds. The e-bike guys who use rc outrunners get similar watts per mile as well.

You just said it yourself. There have been posts by riders that used two 6s5Ah and they had slightly more range when they connected it in 12s5Ah (series) than 6s10Ah (parallel). I sort of believe them when I tried it myself, although I wasn't able to record it. When I ran 12s with my Flier ESC, the acceleration was phenomenal and you get to your desired speed right away and happily cruise at it at half-throttle. When I was using 6s, it would take a really long time to get to my desired speed and I would usually be max on the throttle. So my theory is, because it takes time to get to your desired speed and since you are usually always at WOT with 6s, it burns more amps. Don't listen to me, I'm just extrapolating. lol.

I'm an old school rollerblader and I've been messing around lately with newer frames and big wheels. I'm not sure how I would do it without it getting unwieldy, and I can't wait to see your implementation.

P.S. I've been rocking the Razors genesis skates which are basically the exact same as the M12s. I want to get a set of Xjsados soon too though for powerblading / Big wheel setup.

Where do you plan to mount the cells?

P.S.S. What are those clear UFS frames? Did you make them? Most of the frames That I've seen that are that large are made out of metal, I'd love to try them out.

chinyp wrote:I plan to get my hands on these motors first before I could do anything else~ Van, if you really did wreck that motor....could you mail it to me?? Haha
I wan to use those dimensions to make my geared hub....
Btw, where and which manufacturer you sourced it from? How much was the surcharge you mentioned?? I wanna just order it and pay for the surcharge....desperate and impatience here....

Sorry there is a misunderstanding, I haven't wrecked any motor! Currently the situation is :
-I have 2 EMax BL5345 which are powerful but too big ;
-I wait (together with the group buy) for the factory (the one who builds EMax motors) to finish 5 customs 85kv motors.

They agreed to get on the adventure because I plan massive orders later from them, otherwise they don't take sample requests I'm afraid but don't worry there will be more available later!

henryv wrote:Can't wait to see this.

I'm an old school rollerblader and I've been messing around lately with newer frames and big wheels. I'm not sure how I would do it without it getting unwieldy, and I can't wait to see your implementation.

P.S. I've been rocking the Razors genesis skates which are basically the exact same as the M12s. I want to get a set of Xjsados soon too though for powerblading / Big wheel setup.

Where do you plan to mount the cells?

P.S.S. What are those clear UFS frames? Did you make them? Most of the frames That I've seen that are that large are made out of metal, I'd love to try them out.

Thank you! The frame is a Kizer advance and the cells will be mounted right in the baseplate